1. Field of the Invention
The present invention relates to an order changing method in a corrugating machine for manufacturing a corrugated fiberboard sheet. More particularly, the present invention relates to an order changing method in a corrugating machine having the paper patch and sheet taking arrangement of a corrugated fiberboard web in such a manner that dividing slits of the corrugated fiberboard web are set on an almost straight line before and after an order change.
2. Description of the Related Art
FIG. 5 is a conceptual view showing a part of the downstream side of a corrugating machine for manufacturing a corrugated fiberboard sheet. In FIG. 5, a slitter scorer state 101 is provided on the right side and a cut-off stage 102 is provided on the left side. Cutting and creasing are performed while a corrugated fiberboard web 103 is running from the slitter scorer stage 101 toward the cut-off stage.
The slitter scorer stage 101 comprises one cutter 104 and two slitter scorer devices 105a and 105b. One of the slitter scorer devices 105a and 105b is usually operated, and the other is kept with the setting switched to cutting conditions corresponding to the next order.
Trim ducts 150a and 150b for sucking a trim of the corrugated fiberboard web 103 are provided behind the slitter scorer devices 105a and 105b, respectively.
The cut-off stage 102 positioned on the downstream side of the slitter scorer step 101 comprises upper- and lower-stage cut-off devices 106 and 107 for cutting the corrugated fiberboard web 103 in a transverse direction orthogonal to a running direction thereof (hereinafter referred to as a flow direction or a progress direction).
According to such a corrugating machine 110, the corrugated fiberboard web 103 stuck by means of a double facer (not shown) which is provided on the upstream side is in the progress direction of the corrugated fiberboard web 103 at the slitter scorer stage 101, and is then cut to have the same length in the transverse direction at the cut-off stage 102. Consequently, a plurality of rectangular corrugated fiberboard sheets 111 and 112 shown in FIG. 6 can be manufactured. The corrugated fiberboard sheets 111 and 112 are stacked by means of a stacker.
Next, description will be given to a sheet taking operation to be performed by the corrugating machine 110. The above-mentioned cut-off operation means a so-called double cut-off operation to be performed by the two cut-off devices 106 and 107. FIG. 6 is a plan view showing the sheet taking operation for processing the corrugated fiberboard web 103 by the double cut-off operation.
The corrugated fiberboard web 103 is cut into a plurality of portions along slitter cutting lines 120 in the flow direction of the corrugated fiberboard web 103 at the slitter scorer step 101. By using, as a boundary, a dividing slit M which is one of the slitter cutting lines 120, for example, an upper web 103a positioned on the upper side in FIG. 6 and a lower web 103b are fed to the upper-stage cut-off device 106 and the lower-stage cut-off device 107 respectively, and are cut by cut-off lines 121 and 122 in the transverse direction of the corrugated fiberboard web 103 and are cut away at equal intervals in the flow direction respectively. Thus, the rectangular corrugated fiberboard sheets 111 and 112 having different dimensions can be manufactured in the upper-stage cut-off device 106 and the lower-stage cut-off device 107, respectively.
For example, when the corrugated fiberboard sheets 111 and 112 having different sizes are being processed by the upper-stage cut-off device 106 and the lower-stage cut-off device 107, a dimension of the sheet to be cut by the cut-off devices 106 and 107 is changed in some cases. This change is referred to as an order change. The order change is performed in the following two cases.
(1) Only one of the upper- and lower-stage cut-off devices 106 and 107 is subjected to the order change.
For example, the corrugated fiberboard sheets 111 and 112 are manufactured in independent production lots by the upper- and lower-stage cut-off devices 106 and 107, respectively. Therefore, even if a predetermined number of corrugated fiberboard sheets have been manufactured in one of the upper and lower stages, the production is rarely finished at the same time in the other stage. Accordingly, if the production is completed in one of the upper and lower stages (for example, the upper stage side 106), it is necessary to newly change the order. In addition, if the kind of paper does not need to be changed but only the width of the paper is to be changed, the production should be continued with the same order in another stage (for example, the lower stage side 107).
(2) Before and after the order change, both the upper- and lower-stage cut-off devices 106 and 107 are subjected to the order change. At this time, it does not matter if the kind of paper is changed.
Various order changing methods to be used in the corrugating machine 110 have conventionally been proposed. As one of examples, a method described in Japanese Unexamined Patent Publication No. Hei 6-210772 will be described below with reference to FIG. 7. FIG. 5 described above illustrates equipment based on the method.
FIG. 7 shows a case in which the upper-stage cut-off device 106 maintains the same order and the lower-stage cut-off device 107 performs an order change to manufacture a product having a smaller width. Accordingly, a web width is reduced according to the width of the product before and after the order change.
First of all, a corrugated fiberboard web 103x having an old order is processed by the slitter scorer device 105a shown in FIG. 5. In the slitter scorer device 105a, the corrugated fiberboard web 103x is cut by a slitter cutting line 120x and a dividing slit Mx shown in FIG. 7. Therefore, both ends 160x and 160x of the corrugated fiberboard web 103x in a transverse direction act as trims. The trims 160x and 160x are sucked into the above-mentioned trim duct 150a (150b) and are removed.
Next, upper and lower shafts of the slitter scorer device 105a are opened in a proper position on this side of a paper patch portion, thereby stopping the cutting. In advance, a trim cutting line 130 should be formed on the ends of the corrugated fiberboard webs 103x and 103y by a rotary shear (not shown).
The reason why the trim cutting line 130 should be formed will be described below. In a case where the trim cutting line 130 is not formed on the trim 160x of the corrugated fiberboard web 103x having an old order, there is a possibility that the corrugated fiberboard web 103x might be pulled by the trim 160x and hit against the trim duct 150a, thereby causing jam-up or the like.
Furthermore, if the trim cutting line 130 is not formed on trims 160y and 160y of the corrugated fiberboard web 103y having a new order, the trims 160y and 160y are kept coupled to the corrugated fiberboard web 103y so that the corrugated fiberboard web 103y is not sucked into the trim duct 150a. Alternatively, if the corrugated fiberboard web 103y is forcedly sucked into the trim duct 150a with the trims 160y and 160y kept coupled to the corrugated fiberboard web 103y, there is a possibility that an inconvenience might be caused, that is, the trim duct 150a becomes clogged.
In order to denote parts before and after the order change by designations, particularly, an old order before the order change is indicated as x, and a new order after the order change is indicated as y.
Next, a paper patch portion is interposed to form a proper space, thereby operating the slitter scorer device 105b. Thus, the cutting of the corrugated fiberboard web 103y having a new order is started. In an order changing area 131, slitter cutting lines 120x and 120y having old and new orders are not provided. A dividing slit N is formed in the order changing area OC by a cutter 104 and the corrugated fiberboard web 103 to be fed to the upper- and lower-stage cut-off devices 106 and 107 is divided into two portions. Consequently, the order change can be performed without separating the corrugated fiberboard web 103x having the old order from the corrugated fiberboard web 103y having the new order before and after the order change.
Conventionally, the corrugated fiberboard web 103 is generally passed with the centers of the old and new corrugated fiberboard webs 103x and 103y in the transverse direction aligned with the center of the corrugating machine 110. On the assumption that such a method is used, equipment itself has been designed. For example, generally, a stage roll and a pressure roll are pressurized by a single facer, a double facer and the like symmetrically horizontally based on the center of a machine. Accordingly, dividing slits Mx and My of the old and new webs for dividing the corrugated fiberboard webs 103x and 103y to be fed to the upper- and lower-stage cut-off devices 106 and 107 are changed in the transverse direction, respectively.
However, the conventional order changing method in the corrugating machine described above has had the following problems.
(1) The order changing area OC is provided on the paper patch portions of the old and new corrugated fiberboard webs 103x and 103y. Correspondingly, defective sheets 131x and 131y which cannot become products have lengths increased.
(2) Moreover, the positions of the dividing slits Mx and My are moved in the transverse direction. Consequently, it is necessary to reset the vertical distributing position of a slat of a web director 132 shown in FIG. 5 in a very short time according to a timing of passage through the order changing area OC. If the setting cannot be well performed, the corrugated fiberboard web 103 cannot be supported stably so that jam-up and poor precision are caused.
(3) Furthermore, the stacking portion of the stacker provided on the upper-stage cut-off device 106 cannot perform a continuous stacking operation because a sheet discharge position is changed in the transverse direction irrespective of the same order. Therefore, it is necessary to expel a stack once during the stacking operation and to newly perform the stacking operation.
In consideration of the above-mentioned conventional problems, it is an object of the present invention to provide an order changing method in a corrugating machine which can decrease the number of defective sheets generated during an order change and can perform a continuous stacking operation in a stacking portion of an upper-stage stacker.
In order to achieve the above-mentioned object, the present invention provides an order changing method in a corrugating machine comprising a slitter scorer device and a plurality of cut-off devices, the method comprising, in the slitter scorer device, the steps of:
cutting a corrugated fiberboard web along slitter cutting lines in a running direction thereof;
dividing the cut corrugated fiberboard webs into at least two portions by using, as a boundary, a dividing slit which is one of the slitter cutting lines; and
feeding the divided corrugated fiberboard webs to the cut-off device, and
the method comprising, in the cut-off device, the steps of:
cutting and separating each of the corrugated fiberboard webs in a direction orthogonal to the running direction thereof,
supplying the corrugated fiberboard web having a new order followed by the corrugated fiberboard web having an old order; and
setting a dividing slit of the corrugated fiberboard web having an old order and a dividing slit of the corrugated fiberboard web having a new order on almost the same straight line when making a change from the corrugated fiberboard web having an old order to the corrugated fiberboard web having a new order.
The above-mentioned order changing method can be employed in upper- and lower-stage cut-off devices, for example, and can continuously perform production with the same order in the upper-stage cut-off device and can cope with an order change in which the kind of paper is not changed but only a width thereof is to be changed in the lower-stage cut-off device. In this case, it is not necessary to change the position of a stacker provided on the upper-stage cut-off device and to perform a stacking operation again. Furthermore, the order changing method can also cope with an order change in which the web widths should be changed in the upper- and lower-stage cut-off devices.
Moreover, other embodiment of the present invention is the order changing method in a corrugating machine, further comprising the step of cutting both ends in the cross direction of the corrugated fiberboard webs having new and old orders and sucking a trim obtained by the cutting by means of a trim duct.
And, the present invention can further adopt the order changing method in a corrugating machine, wherein means for cutting the corrugated fiberboard web in the slitter scorer device serves to perform the cutting by means of slitter knives provided vertically in the slitter scorer device.
According to the above-mentioned order changing method, the dividing slits are set on almost the same straight line before and after the order change. Therefore, an extra length equivalent to the conventional order changing area is eliminated. Therefore, the loss of sheets can be reduced.
As described above, the order changing method in the corrugating machine according to the present invention has the following effects.
(1) The position of the dividing slit is not changed in the transverse direction before and after the order change. Therefore, it is not necessary to change the setting of a web guide. Consequently, the causes of the generation of jam-up can be reduced.
(2) In a case where one of the cut-off devices continues the same order, the position of the stacker is not changed in the transverse direction after a cut-off operation. Therefore, it is not necessary to perform the stacking operation again. Consequently, the causes of the disorder of sheets on the stacker and the jam-up can be eliminated.
(3) The extra length equivalent to the conventional order changing area is eliminated. Therefore, it is possible to decrease the loss of sheets.